The aim of this study is to evaluate three diagnostic methods for assessing small bowel disease in patients with suspected or known Crohn's disease. All patients are examined with ileo-colonoscopy, capsule endoscopy, MRI and CT of the small bowel within 14 days. However, capsule endoscopy is not performed in patients with stenosis detected at ileo-colonoscopy, MRI and/or CT. All investigations are described in a similar pre-defined and standardized fashion and the radiologist and physician responsible for describing the findings at MRI, CT and capsule endoscopy are blinded to the findings at ileo-colonoscopy. The physician in charge of treatment receives a randomised result of either MRI, CT or capsule endoscopy. Thereafter patients are followed during 12 months to evaluate differences in clinical outcome depending on the randomized result. In combination with the diagnostic validity and inter-observer agreement of MRI, CT and capsule endoscopy we seek to establish the optimal diagnostic strategy in these two patient categories.